OpenSSH can take advantage of port forwarding too, and does it with compression. For instance I cvsup'd over a proxied ssh session from my office through the company firewall off my home machine to the cvsup mirror with:
ssh -C -L 5999:cvsup11.freebsd.org:5999 -N ssh-server

Then on the computer I wanted to cvsup:
cvsup -g -L 2 -h localhost /path/to/stable-supfile

It just works! I can take advantage of an already installed (stronger, too) crypto program to take advantage of port forwarding.